Live Exposure Defense: From CVE to Confirmed Exposure in 12 Hours – See more

Back
New CVE Detected

CVE-2026-86304 – SAML Authentication Bypass – MojoX::Authentication (Perl) before 0.006

Be the first to know when new zero-days emerge:

Subscribe to Email Alerts
Subscribe to RSS Feed

Summary

CVE-2026-86304 is a critical SAML authentication bypass vulnerability (CWE-347: Improper Verification of Cryptographic Signature) affecting MojoX::Authentication, a Perl module that provides SAML2-based login for Mojolicious applications. Versions before 0.006 fail to configure a trust anchor when validating SAML responses, allowing a remote, unauthenticated attacker to forge a self-signed SAML assertion and impersonate any user. The flaw carries a CVSS v3.1 base score of 9.8 (Critical).

Technical details

  • Root cause: The parse_assertion function in MojoX::Authentication::Model::SAML2 constructs a Net::SAML2::Binding::POST object without supplying a cacert, cert_text, or anchors argument (i.e., no trust anchor). It then passes the parsed XML to Net::SAML2::Protocol::Assertion->new_from_xml, supplying the IdP signing certificate as cacert.
  • Underlying library behavior: In Net::SAML2 versions before 0.86, the cacert supplied to Assertion->new_from_xml is only enforced against encrypted assertions. For unencrypted assertions, signature verification falls back to validating against the X.509 certificate embedded in the response’s own KeyInfo/X509Certificate element — meaning the response is effectively validated against a key the attacker controls.
  • Attack vector: Network (AV:N), no privileges or user interaction required. An attacker initiates a SAML login flow and submits a SAML response signed with their own, self-generated certificate. Because the audience restriction, InResponseTo, and timestamp checks that follow signature validation are all satisfiable by an attacker who controls the entire forged response, the assertion is accepted as valid.
  • Impact: Complete authentication bypass — an attacker can authenticate as any user (including privileged accounts) by supplying an arbitrary NameID in a self-signed assertion, leading to full compromise of confidentiality, integrity, and availability of the protected application.
  • Related issue: This bypass is closely tied to a companion vulnerability in the underlying Net::SAML2 library itself (fixed in Net::SAML2 0.86), where Binding::POST and Assertion verification routines permitted signature checks to succeed against unanchored, response-supplied certificates when no trust anchor was configured by the caller.

Affected software

  • MojoX::Authentication (CPAN, Perl) — all versions prior to 0.006 (versions 0 through 0.005)
  • Deployments remain exposed even on patched MojoX::Authentication if the underlying Net::SAML2 dependency is older than 0.86, since that library’s trust-anchor enforcement is part of the overall fix chain.

Severity

  • CVSS v3.1 Base Score: 9.8 (Critical)
  • Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Mitigation and recommended actions

  • Immediate: Upgrade MojoX::Authentication to version 0.006 or later (released July 31, 2026), which correctly supplies a trust anchor when building the SAML binding/assertion validation path.
  • Dependency upgrade required: Ensure the underlying Net::SAML2 library is also upgraded to version 0.86 or later. This release makes a trust anchor (cacert/cert_text) mandatory for verifying any Response or Assertion and closes the unanchored-signature validation path; note this is a breaking change for any code that previously relied on the permissive default.
  • If immediate patching is not possible: Installing Net::SAML2 0.86 or later alone will cause affected SAML logins to fail closed (rather than accept forged assertions), acting as an interim workaround until MojoX::Authentication can be upgraded.
  • Defense in depth: After patching, consider enabling the new opt-in require_signed_assertion and require_signed_response options introduced in Net::SAML2 0.86, and audit SAML SP configurations to confirm a trust anchor (IdP certificate) is explicitly configured wherever SAML responses or assertions are parsed.

References

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report

How IONIX’s External Exposure Management Platform Detects and Validates
Zero-Days to Shrink MTTR

1

Map your entire attack surface (continously)

IONIX uses multi-factor discovery methods, including DNS analysis, certificate mapping, metadata inspection, and more, to automatically map every internet-facing asset across your environment. This includes cloud instances, third-party platforms, shadow IT, and even forgotten infrastructure that traditional tools miss.

2

Monitor for new CVEs

Dozens of threat intel feeds using agentic technology are continuously analyzed to detect the appearance of proof-of-concept code, exploit kits, and indicators of active targeting. IONIX goes further by applying AI to proactively evaluate whether emerging vulnerabilities are likely to be exploited, even before PoCs go public.

3

Identify Potential External Exposures

Not all CVEs matter. IONIX filters vulnerabilities by asking attacker-centric questions: Can it be reached from the internet? Does it require authentication? Is it being exploited in the wild? This dramatically reduces noise and focuses teams on threats that can actually be weaponized.

4

Create Safe, Scalable Exploit Validations

IONIX transforms real-world PoCs into safe, non-intrusive test payloads that can be run in production environments without disruption. These simulations are precisely targeted to the systems that are vulnerable, ensuring rapid validation without unnecessary load.

5

Execute Exploit Validations

By combining context about software stack, versioning, exposure status, and reachability, IONIX ensures that only the right payloads are executed against the right assets, maximizing efficiency and minimizing risk.

6

Drive Fast and Actionable Remediation

Results are routed through integrations with ticketing, SOAR, and SIEM tools. Issues are written in plain language, bundled into remediation clusters, and prioritized based on asset criticality, exploitability, and blast radius. This shortens mean time to remediation (MTTR) and empowers teams to act with confidence.

Are you exposed?

Get a free report of your organization’s exposure to this CVE and threat

  • Mapping of all Assets with this Technology
  • Identification of potentially exposed assets to this CVE
  • Confirmation of verified exploitable assets
Get Exposure Report
Close

Subscribe to Threat Center RSS

Copy/paste the link below into your preferred RSS reader or follow these instructions to subscribe to Slack alerts.

Open RSS feedSlack setup instructions

Close

Get Real-Time CVE Alerts to Your Email

Be the first to know when new zero-days emerge